A bench vise is used in holding a workpiece for manufacturing. Such a workpiece must be gripped in some manner and held steadily to the cutting head of a milling machine. It is especially important that the workpiece be held consistently especially when manufacturing the same product time and time again. Consider for instance a long production run of 1,000 units. Adjustments are made in the milling machine to locate the cutting head with respect to the table and to program moves of the cutting head with respect to the first workpiece. All of this requires repetitive and precision attachment to the workpiece temporarily to the table of the milling machine. The milling machine table normally supports a bench vise on it. The vise is opened and then closed to clamp on a workpiece. The accuracy of the programmed movements as well as the accuracy of the finished product is in large part dependent on the accuracy of the workpiece with respect to the milling machine. In turn, if the milling machine starts at the wrong position with respect to the workpiece, it will finish at the wrong position. Repeatable positioning is essential.
The most reliable mode of operation of the equipment is therefore dependent on accuracy in positioning with respect to the vise. Accuracy in the use of the vise is extremely important. The vise is normally constructed so that clamping a workpiece between the two jaws of the vise encounters a measure of variation. The risk a is dependent on accurate tracking of the vise as it is opened and closed. In many vise constructions, the vise will work quite well when the workpiece is centered with respect to a centerline axis of the vise, i.e., an axis defined by the screw which opens or closes the jaws. While the jaws might have a relatively large surface, when the workpiece is off center, the jaws may cant ever so slightly. In effect, the faces defining the two jaws will no longer be positioned in a parallel fashion. In other words, the movable jaw may be canted with respect to the fixed jaw and create a misalignment which is not necessarily seen by the eye but which derives from improper operation of the jaws of the vise during movement.
In one aspect, the workpiece held by the jaws of a vise in accordance with the present disclosure can be off center and yet not cant or cock the jaws inappropriately. In another aspect, the workpiece is gripped by the movable jaw so that off center gripping does not jeopardize proper jaw operation. Specifically, the device closes in such a fashion that misalignment does not occur. This is accomplished by constructing the movable jaw so that it travels on left and right ways. It will not cant or otherwise wedge. This avoids wedging difficulties. This assures continued alignment of the device when grasping a workpiece between the two jaws. The movable jaw is constructed with a way gripping lower surface. The jaws include a tapered or sloping surface. This repositions so that the jaws track true to the centerline axis, i.e., the jaw face is precisely vertical.
The present disclosure is an improved vise featuring a movable jaw which is guided by a screw to move along a pair of ways guiding the moving jaw. The moving jaw is adjusted to maintain a face which is precisely parallel with the fixed jaw face. The moving jaw is constructed of an upper component which travels on the ways. It is, however, internally hollow so that a U-shaped lower member inserts into it, the insert being a U-shaped bottom member telescoped into a U-shaped mating opening in the top jaw member. The two jaw members contact at a tapered face which cants or tilts the upper jaw member so that the movable jaw construction can be leveled. Leveling assures that the upper and lower jaw members cooperate, thereby interacting with a tapered face between the two to change the relative angle. In effect, the movable jaw face is maintaining precisely parallel and overcomes off center mounting of the workpiece.